diff --git a/program/include/rcube_output_json.php b/program/include/rcube_output_json.php
index 7b5510dfe..eb1a9380d 100644
--- a/program/include/rcube_output_json.php
+++ b/program/include/rcube_output_json.php
@@ -36,18 +36,6 @@ class rcube_output_json extends rcube_output
     public $ajax_call = true;
 
 
-    /**
-     * Set environment variable
-     *
-     * @param string $name Property name
-     * @param mixed $value Property value
-     */
-    public function set_env($name, $value)
-    {
-        $this->env[$name] = $value;
-    }
-
-
     /**
      * Issue command to set page title
      *